In recent years, along with the increased number of patients suffering from diabetes, self-monitoring of blood glucose, adapted to allow a patient to daily monitor a variation in blood sugar level of the patient, has come to be recommended.
The measurement of a blood sugar level is performed by using a blood glucose monitoring apparatus in accordance with a manner of mounting a strip of test paper, specified to be colored depending on an amount of glucose in blood, to the apparatus, supplying and diffusing blood to and in the test paper to color the test paper, and optically measuring the degree of coloring of the test paper, thereby quantifying a blood sugar level.
Prior to such measurement, the sampling of blood by a patient is performed by puncturing the skin of an epidermis with a puncture device including a puncture needle or a blade and compressing a portion, around the puncture site, with a finger, for example, so as to squeeze blood therefrom.
A finger tip of a patient is suitable as a portion from which blood is to be sampled because blood capillaries are concentrated at the finger tip; however, since nerves are also concentrated at the finger tip, the puncture of the finger tip may inflict a pain on the patient. The puncture of a finger tip may inflict not only a large bodily pain and a large psychic burden but also a feeling of fear against puncture on a patient, and for this reason, many patients may often fail to continue the self-monitoring of blood glucose.
The prior art monitoring of a blood glucose has a problem in terms of operability because the puncturing operation, the blood sampling operation, and the measuring operation are separately performed.
A blood glucose monitoring apparatus capable of solving such a problem is known in Japanese Patent Application Nos. Hei 10-183794 and Hei 10-330057, which includes a puncturing unit and a measuring unit integrated with each other, and a suction means for squeezing blood.
In operation of the above blood glucose monitoring apparatus, a finger tip is first touched to the tip of a chip so as to air-tightly seal the tip opening.
The finger tip is then punctured with a puncture needle projecting from the tip opening, and in such a state, a sucking means is operated (to cause an evacuation state), to suck blood from a puncture site, thereby sampling the blood. The blood sugar level of the sampled blood is then measured by a measuring unit.
The above blood glucose monitoring apparatus, however, has a problem that since the blood is sucked at a constant pressure, it takes a relatively long time to obtain an amount of blood necessary for measurement of a blood sugar level.
Another problem is that since a gap between the finger and the tip of the chip may occur depending on a position of the finger touched to the tip of the chip, it fails to sufficiently reduce the pressure in spite of the operation of the sucking means, and therefore it fails to obtain an amount of blood necessary for measurement or it takes a relatively long time to obtain a sufficient amount of blood.
One example of a chemical formula between glucose (D-Glucose) in blood and a reagent at the time of measurement of a blood sugar level is shown below, and as is apparent from the chemical formula, a sufficient amount of oxygen is required for measurement of blood sugar level. In other words, if the amount of oxygen is insufficient, it fails to accurately measure a blood sugar level.

According to the prior art blood glucose monitoring apparatus, however, a blood sugar level may be often measured in the evacuation state, and in this case, there may occur a problem that a blood sugar level cannot be accurately measured because of insufficient amount of oxygen.
To solve such a problem, the present inventor has found that oxygen (component, necessary for measurement, in atmospheric air) can be sufficiently supplied by releasing or relieving the evacuation state prior to measurement, and has accomplished the present invention on the basis of such knowledge.
An object of the present invention is to provide a body fluid component measuring apparatus capable of accurately, certainly measuring a specific component in blood for a short time.